In situ-templated hydrothermal synthesis of Fe-doped anatase nanorods

Anatase single crystal nanorods with aspect ratios of 4-10 and diameters of 70-100 nm were prepared by hydrothermal treatment of tetraethylammonium hydroxide peptized titania sol doped with Fe(III) cations at 200 °C. Two types of iron sources were used as dopants: (i) Fe(NO3)3, which could form (alpha)-FeOOH during the hydrothermal synthesis; (ii) hydrothermally synthesized (alpha)-FeOOH. The formation of anatase nanorods in the Fe^3+ doped titania could be attributed to porous goethite ((alpha)-FeOOH) rods formed during the hydrothermal treatment. The in situ formed (alpha)-FeOOH template could lead to well dispersed anatase nanorod crystals in contrast to the strongly agglomerated rods obtained when adding as-synthesized (alpha)-FeOOH. The templates do not need to be removed since a solid solution forms between the Fe ions and anatase during hydrothermal treatment.